Philippine police today arrested two men in what the government called a Muslim extremist plot against Pope John Paul II, who was visiting Manila as part of a four-nation tour of Asia. Manila press reports said police are searching for about 20 foreigners in the alleged conspiracy, which reportedly targeted U.S. airlines. Two Pakistani men allegedly involved in the plot were arrested last Friday near the residence of the Vatican ambassador. Police sources told Manila reporters that the men had bomb-making materials in their hotel rooms. Police reportedly are now seeking a 26-year-old Kuwaiti-born "electronics expert" believed to be the ringleader. The conspirators are thought to have slipped into the country in small groups over a period of weeks, entering through the southern island of Mindanao, a Muslim enclave.